1. Field of the Invention
The present invention relates to rotational angle sensors for detecting the rotational angle of rotary members.
2. Description of the Related Art
Throttle control devices have been used for electronically controlling the flow rate of intake air supplied into an engine, such as an internal combustion engine of an automobile. Some of the throttle control devices have rotational angle sensors that serve as throttle sensors for detecting the rotational angle of a motor shaft of a motor driving a throttle valve. For example, Japanese Laid-Open Patent Publication No. 6-264777 teaches such a rotational angle sensor.
Various types of rotational angle sensors are known to be used for throttle control devices. For example, Japanese Laid-Open Patent Publication No. 2003-57071 teaches a rotational angle sensor that has a magnetic detection device and a printed circuit board. The magnetic detection device includes a pair of magnets disposed in opposing relation to each other with respect to a rotary member (i.e., on either side of a rotary member). The rotational angle of the rotary member is detected based upon a magnetic field produced between the magnets. More specifically, the detection device has a detection element that detects the density of the magnetic flux (i.e., the intensity of the magnetic field) produced between the magnets. The detection device then outputs detection signals representing the detected rotational angle. The detection device typically has connecting terminals that are electrically connected to the printed circuit board.
In order to facilitate the handling of the rotational angle sensor of a type disclosed in Japanese Laid-Open Patent Publication No. 2003-57071, the magnetic detection device may be disposed within a holder and the printed circuit board may be attached to the holder. The holder may then be mounted to a fixed place. However, in a situation where such a holder is incorporated, there has been a problem that in some cases the detection accuracy cannot be ensured.